Large amounts of organic waste are generated annually from agricultural plantations, animal farms, mills, food processing plants and industrial plants. The amount of organic waste generated has been increasing each year as the agro-food industries expand. Consequently, the disposal of these wastes has been a major concern in recent years.
The conventional methods of disposal of organic waste are landfilling and incineration. Landfills require extensive areas and are both unsanitary and unsightly. Furthermore, landfills create problems such as the leaching of harmful chemicals into the soil, contaminating ground water, and causing loss of essential nutrients into the soil. Incineration is expensive, energy-intensive and creates environmental problems. For example, Malaysia, which has over 2.65 million hectares of oil palm plantations and, can generate 90% total biomass of waste annually of all harvested materials, has prohibited open burning of organic waste to prevent air pollution. The European Union has also mandated a general ban on landfilling of organic waste in 2005.
Biological treatment of organic waste has been applied in an attempt to address the problem of organic waste disposal. Biological treatment of organic waste can convert organic waste into harmless and value-added products. Biological treatment methods use naturally-occurring microorganisms to degrade complex hydrocarbon-contaminated waste into simpler low-carbon, non-toxic residues via fermentation. Desirably, the product residues of biological treatment methods are typically harmless and therefore there is typically no requirement for any post-process treatment, storage or discharge. However, the natural composting of organic waste, such as agricultural waste and animal manure, can take up to six months to mature and achieve a carbon to nitrogen ratio (C:N ratio) that is suitable for use as fertilizer, and typically results in a product with relatively low NPK values (typically less than 2) and is therefore less useful and less valuable as an organic fertilizer.
There is a need to provide a process for the treatment of organic waste that overcomes, or at least ameliorates, one or more of the disadvantages described above.
There is a need to provide an efficient, simple, cost-effective, and environmentally friendly process for treatment of organic waste to reduce the C:N ratio of the organic waste and produce organic fertilizers of high NPK values.